With the rapid development of the distributed resources, the operation mode of power distribution network is becoming more and more diversified. The traditional nonlinear ACbased programming model has many lacks in the aspect of calculation. With the rapid development of the distributed resources, the operation mode of power distribution network is becoming more and more diversified. The traditional nonlinear ACbased programming model is lack in the aspect of calculation. In view of this, this paper presents an active power distribution network planning model based on linearized constraints. Firstly, the basic principle and analysis method of distribution network model linearization are presented from two aspects, the power flow linearization and the distribution network connectivity linearization. By analyzing the objective function and constraint conditions of distribution network planning, a mixed integer linear rule (MILP) model is further proposed, which can be solved by a general mathematical optimization toolkit. Finally, simulations under different conditions are carried out and the linearization planning model of distribution network are compared with the nonlinear programming model. It is shown that the proposed method is feasible and effective and a new method is provided for the future planning and operation research of the active distribution network.